Oracle 8i JServer leaks 100Mb per hour

Question

The 8.1.5 aurora jvm appears to leak a significant amount
of memory whenever a session is ended or a new session is
created. Is this a known bug? Is there a workaround?
In particular, this is a problem for job queues that
execute java. In only a few hours several 100Mb of ram
will leak for each snp process on my system. I assume
this is because the job queues start a new session
for each job.
Example:
PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME COMMAND
1405 oracle 0 0 220M 182M 48144 S 0 0.0 19.2 7:34 ora_snp0
8023 oracle 3 0 35988 35M 33956 D 0 4.9 3.7 0:04 oracle
The snp0 process has at this point been executing a few hundres
jobs over a period of two hours. The second process has been
executing the same java code, but within one session.
The most intersting part is that the memory isn't shared,
but my snp processes will lose hundreds of Mb each, quickly
using up all system ram.
I've traced the leaks to being static variables in java.
The following test code shows what i believe is the problem:
class Boog
String name;
public Boog (String n) { name = n; System.out.println ("Boog "+name+" init"); }
protected void finalize () { System.out.println ("Boog "+name+" cleanup"); }
public void print () { System.out.println ("Boog "+name+" printing"); }
class Test
static Boog boog = new Boog("one");
public static String test ()
boog.print();
Boog boog2 = new Boog("two");
boog2.print();
boog2 = null;
return "done";
loadjava -u scott/tiger -r -v Test.java Boog.java
create function javatest return string as
language java name 'Test.test () return java.lang.String';
select javatest from dual;
select javatest from dual;
connect scott/tiger
select javatest from dual;
now lets look at the trace file for the process:
Oracle8i Enterprise Edition Release 8.1.5.0.2 - Production
With the Partitioning and Java options
PL/SQL Release 8.1.5.0.0 - Production
ORACLE_HOME = /ora01/app/oracle/products/8.1.5
System name: Linux
Release: 2.2.14
Version: #9 SMP Sun Mar 5 18:52:44 CST 2000
Machine: i686
Redo thread mounted by this instance: 1
Oracle process number: 15
Unix process pid: 2082, image: oracle@localhost (TNS V1-V3)
*** SESSION ID:(19.600) 2000.04.01.22.39.43.794
Boog one init
Boog one printing
Boog two init
Boog two printing
Boog two cleanup
*** 2000.04.01.22.40.27.455
Boog one printing
Boog two init
Boog two printing
Boog two cleanup
*** SESSION ID:(19.602) 2000.04.01.22.40.35.499
Boog one init
Boog one printing
Boog two init
Boog two printing
Boog two cleanup
As expected Boog one is reused in the second call in the
first session. Boog two is immediately cleaned when it's
nulled out.
Boog one is never cleaned up when the session is ended!
Help!...
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Answer 1

To clean up your memory at the end of a call
you may use the End-Of-Call Callback.
The following code is the example given by Oracle in their documentation:
import oracle.aurora.memoryManager.Callback;
import oracle.aurora.memoryManager.EndOfCallRegistry;
public class EndOfCallExmpl extends Object {
static String cachedField = null;
private static Callback thunk = null;
static void clearCachedField() {
System.out.println("before clearing the cached field");
cachedField = null;
thunk = null;}
public static String getCachedField() {
if (cachedField == null) {
// save thunk in static field so it doesn't get reclaimed
// by garbage collector
thunk = new Callback () {
public void act(Object obj) {
EndOfCallExmpl.clearCachedField();
// register thunk to clear cachedField at end of call
EndOfCallRegistry.registerCallback(thunk);
// finally, set the cached field
cachedField = "hello world";
return cachedField;}
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